Telephone-exchange system



PATENTED AUG. 25, 1908.

H. G. WEBSTER.

TELEPHONE EXCHANGE SYSTEM.

APPLIOATION FILED AUG. 4,1904.

terminal of the subscriber s line.

UNITED STATES- PATENT OFFICE. I

HARRY e. WEBSTER, or CHICAGO, ILLINUIS, ASsIG OR TO MILO e. KELLOGG, OF CHICAGO, ILLINOIS.

I TELEPHONE-EXCHANGE-SYSTEM.

v Chicago, countyof Cook, and State of Illi nois, have invented certain new and useful Improvementsin Tele hone-Exchange Systems, of which the fol owing isa full, clear, concise, and exact description, reference be had to the accompanying drawings,

mg forming alpart" of this specification.

My -invention relates to improvements in telephone exchange systems, my object being to provide simplified and improved circu1t arrangements and signaling apparatus. In accordance with myinvention I ro'- vide at the central station a signal control ing electromagnet having two energizing windings, one of which is normally in a circuit uniting the sub-station with the exchange, and controlled by the subscriber. 'Theother winding is the circuitof a third conductor, which circuit is controlled by the operator. This electromagnet in'a preferred'form of my invention is preferably a relay, magnet which serves to control a signal such as a lamp. The signal controlling electromagnet is referably constructed so'that it is ini-. tia y controlled by the subscriber at the substationfwhereby a suitablesignal may be actuated to call the attention of the operator to the fact that the subscriber desires a connection. The signal controlling electromagnet is also adapted to be actuated by the'operator preferably by the insertion of the .connecting plug into a spring jack or switchin J The initia actuation of the-relay may be utilized to light a lamp :as the calling signal, and the final actuation of the relay, which is controlled by the operator maybe utilizedfor rendering the signal inert.- g

I have illustrated my invention in connection with the signal controllin 'electromagnet in the formof a relay,

initial movement under thecontrol of the subscriber, and to partake of a final m ve:

'ment under the control of the operator;

the initial movement serving to actuate the signal for the connection and the .final' movement serving to render the signal in' Specification of Letters Patent. Application filed August 4,

aving a single armature adapted to partake-of anv Patented Aug.'25,.1908. 1904. Sria1 No.219,4 15.

'singlearm'ature adapted to partakefof the .two' distinctive movements, it isapparent that this selective operation may e procured in other ways, and I do not therefore desire to to .this particular method of construction.

in S111 which igure 1' illustrates the line to'the sub-- nections. Fig. 2 shows one form ofcord circuit adapted for association with the line circuit of Fig.. '1, in which the connecting I have illustrated apreferred application of my invention in the accompanymg drawplugs have three contact pieces, the talking strands of the cord being inductively related by means of a repeating induction coil. Fig.

'3 shows ,a somewhat similar cord circuit adapted for association with the same line and having three contact pieces for the plugs, but in which the talking strands of the cord are inductively united by means of condensers.- Fig. 4 illustrates a somewhat different cord circuit adapted for connection with the line, in which the plugs have but Jtwo contact pieces and corresponding cord S t I'aIidS. i 7 I Like characters refer-t0, like parts in the several figures;

Referring to Fig. 1 the subscribersappm ratusshowIi-at A is represented as consisting of the telephone hook switch h, signal bell b,

condenser 0, receiver 1, transmitter t, and induction coil '5 including the said receiver'in its secondary winding. r

' Although I have shown but one arran ement it. will be understood-by those skil ed in. the art that various other arrangements of the subscribers. apparatus may be used, and I v'do not confine myself to the particular arrangement illustrated. I

Under normal conditions .the receiver thecentral -oflice over the. telephone line.-

When, however, the subscriber removes his telephone from its hook, thus, closingthe'f upper contactyof lhook switch h and establishing a relatively-low resistance path for the flow of currentthrough the transmltter t and one winding of the coil 71, the relay 3 at the central ofiicc will be operated by the flow of current from said battery B through winding 4 of the relay contact springs 10 and 9, limbs 1-2 of the telephone ine, contacts 1312 and'll of the relay, and thence to the ofiice return or grounded side of'the battery B. This flow of current through the energizing winding 4 is sufficient to cause the partial attraction of the armature n of the said relay, causing it to close the contacts 87. Said energizing winding 4 is of relatively low resistance and composed of relatively few turns, or otherwise -made of low energizing capacity, so as to prevent the complete energizatien of the said relay and to limit the attraction of its armature, In order that the armature it may alter the contacts between the springs 9-10-1 1-12 and 13, it is necessary that the core of the relay be energized to a greater extent than can be secured through the winding 4. The

closure of contact 87 established a path for the ilow of current from battery B r through lamp (i, eontaet 1211 and to the other pole of said battery. This flow of current causes the illumination of the signal lamp 6 to indicate to the operator that the subscriber hasremovcd his telephone from its hook for the purpose of making a call.

l lach subscribers line is provided with one or more spring jacks each having contively with the contact pieces 14l-1516 of the spring jack. The contact 1o19 coinplctes a circuit from battery through resistance 2t), lamp .25, conductor fit), and wind.- iiig 5 of the relay 3, to the ground or return side of battery 0. The windings 5 is so proportioned, having a relatively large number oi turns, as to cause the complete energization of the realy 3 and the complete attraction ol its armature 11 thus altering the nor lnal contacts between the springs !)1() ll-12]3. Contact lictweci'i. springs 11- i 12 and 13 is now broken, thus opening the circuit through the signal lamp .(5 and disconnecting said lamp circuit from the line and also breaking the. direct connection between limb 2 of the line and the return side of bat- Lory B. (ontact between springs U-lt) is l)l'1ll( ('ll,illUStllfit't)llll.(('lll;l'l.ll(3\\'lIltllllg 1 from the line circuit. ..\s a result of the coin )lctc operation of said relay 3, the line signal 6 is cll'aced, the normal connections oi winding l and battery B to thc .clophone line are broken, and limbs 1 -2 of the line now ten: minate at springs 1415 of the spring jacks without intervening battery or earth connections. The flow of current through resistance 29 and Winding 5 of the relay 3 would now illuminate lamp 25 were the subscribers telephone not removed from the hook. The telephone being off its hook, however, a flow of current is established through'relay 23 as follows: from the active terminal of bat tery C through winding d of the repeating coil, strand 33 of the cord circuit, contacg 1815 of the plug and jack, limbs 1-2o the line, contact 1417 of the plug and jack, strand 31 of the cord, and winding (1 of the repeating coil to the return side of battery 0. This flow of current energizes the relay 23 and closes b its contact the shunt path around lamp 5 including resistance 27. This path being of comparatively low resistance as compared with the lamp the latter remains unlighted at this time. Upon the actuation of the listening key in m the operators set S is brought into inductive relation with the answering plug by means of wind ings a d of the repeating coil 1, and the operator obtains the number of the connection desired. The busy test is secured by touching the plug tip 20 to the thimble 16 of the line wanted in the usual manner; if the line be idle there will be no flow of current as the thimble 16 and tip 20 are normally of the same potential. If, however, the line tested is connected for conversatiomthc potential of thimble 16 Will be raised by its connection with. the plug contact 19 or 22 of the cord used for such switch connectimr, and a flow of current will result from tip 20 through cord strand 32 and windin a, causiin the customary click in thc operatofis receiver 1'. When plugging in to ring, circuit is com pleted from battery (3 through resistance 30,

lamp 26, contact 22-1 6 oi thcphigand spring.

jack, conductor 60, and wind iiig 5 oi" relay 3 associated with the line to he called. As previously explained current llowing over this circuit causes the illumination of lamp 26 and the complete attraction of the ariiiat-urc of relay 3 disconnects the normal earth and battery connections of the line, and the signal associated therewith. The operator rings in the usual manner by depressing the ringing key I." lit. When the subscriber answers, a circuit being completed. for relay 24 similar to that. described previously for relay 23, the closure of the relay contacts extinguishes lamp 26. \Vhen both subscribers hang up, relays 2324 are thus dcenergized, their contacts separated, and lamps 2.3'aiid .26 illuminated, constituting the-signal 'l'or disconnection Upon the removal ol the plugs all of the apparatusret urns to the normal-position i iown in the drawings.

then the line is associated with the cord circuit'of Fig. 3 its operation is the same as that previously described. Upon the insertlon of a plug, the subscrilers receiver being upon its hook switch, current flows from [return side of the battery, causing its illumibattery C through relay 37, plug and jack contact1916, conductor 60, and winding 5 of the relay 3, causing the complete attraction of its armature. The currentflowing through this circuit also energizes relay 37, causing its contacts to close the circuit of lam normal y closed contacts of relay 35," to the nation. a When the subscriber answers a current from battery C? flows through the windings of relay 35 and thelimbs 1 2 of the line, causing the energization ofrelay '35,, whichby its contacts opens the 'circuit' oflamp 25, extinguishing the same. The operator answers, tests, and rings in the usual manner 'and when switched for conversation the subscribers conversational circuit is completed through condensers e f. As in the case of Fig. 2 the two limbs of the line when switched for conversation terminate at contacts 14-15. of the jacks and are free from battery or earth connections.

When the line is associated with the cord circuit of Hi 4 the operation is substantery C through relay 43, strand 33,. co'ntacttially that o the two previous figures, although the conditions are somewhat differ ent.- The subscriber calls -in the manner previously described, the current through winding 4 of relay 5 causing a limited movement of armature n to close the circuit of the signal lamp 6. The plugs associated with the cord circuit are so constructed that when a plug is inserted (as the answer ing plug 1),) contact 17 will en a e spring 14 of-the jack whil'e contact 40 o t e plug will engage spring 15 and thimble 16 of the jack.

A circuit will thus be completed from bat- 40 16 of the plug and 'jack, conductor aridwinding 5 of: therelay 3, Current flowing throughthis contact will causethe complete attraction of armature n as we 'as the-energi'zation of'relay 43. a If the subscribers receiver were ,u on it's hook switch the signal lamp 25 woul now be illuminated by current from battery C-fiowing' throu'h the contacts of relay 43 and th closed contacts of relay 41.

' however, as the receiver is removed, another circuit has been completed from battery C through contact 40-45 of the plug-and spring jack, limbs 1-2'. of'the -lins, contact 1417'of the spring 'ack and-pkg, strand e of-the battery Current through this circuit en-' orgizes relay 41, causing the separation of its contacts and "prevents lamp :25 fronrlig'bl ing. After, ascertaining the connection desired the operatortes-ts'jin'tlie usual way. 1 If t1. line be busy-aicircuiti'will 25, from battery C through the e. normal y Inasmuch,

tact' 18 +14, and contacts be closedfrom the thimble of the tested line to tip 18, through strand. 32, contact 4748 of relay 44, and throu h the high resistance winding of the test relay 50, which being energized com letes by its contacts a circuit of battery C t rough winding 51 of the operators induction coil, causing the customary click.

It will be noted that while' makingthe test there is no other path for current'fiow from tifp 18 and on'account of the high resistance 0 test relay 50, little or no disturbance is producedupon the line of the tested subscriber. Upon inserting the calling plug, a circuit is completed from battery C through relay 44., strand 34 of the cord, sleeve con-' tact 39 of the plug, thimble 16, conductor 60, and relay-wlnding 5 of the line desired.

Current flowing through this circuit causes for relay 42 similar to that described for relay 41,. its contacts separate, extinguishing lam 2.6. relays'41 and 42 become denergized, their contacts assume the normal position, causing-the illumination of lamps 25-26, and when'the cordvcircuit is disconnected all parts assume the normal position shown in the drawing. In this case as in that of Fig. 3 the talking circuits of the connected sub- When the subscribers hang up,

scribers are completed by means of condensers ef. I When the cord circuit of'Fig. '4 is used it is to be noted that while the lines. are connected for conversation thetalking circuit free from' direct or non-inductive earth or battery 11' connections, although the winding 5 of rela 3 is left-legged toone sideof the line throug the contact 16 -40 of the plug, and spring jack,and that when'a subscriber iscalle'di'the relay 3 is completely actuated bycurrent from battery C. flowing through resistance 52, sleeve 39 of the .calling plug,

winding 5, and that the thimble 16, conductor .60 and circuit of'ringing generator 9 includes conthe plug and spring jack, limbs 1 "2 of thehneand the common circuits of the cen tral office battery. While separate batteries cated in the" various figures, itwill be well understood bythose skilled inthe art that in either. of the'three systems. indicated-a. single source of current may-be used. It is also ."to The {understood 'that the various attraction of the armature n and that the winding 4 shall produce a limited energization thereof suflicient only .to cause the partial attraction of the said. armature n.

It will also be obvious to those skilled in theart that my, invention is not confined in its application to the switch board systems illustrated in the drawing, but that it may be embodied and utilized in other structures. Also that many modifications may be made without departing from the spirit of my invention, and I therefore do not wish to be limited to the precise structure shown, but

I claim 1. In .a tele hone exchange system the combination oi a telephone line connecting a sub-station with the central office, a switching terminal having two contact pieces conductively associated with the two sides of said line and a testing contact piece adapted to be connected in a circuit local to the exchange, a signal receiving electromagnet associated with said line, having an energizing winding and source of current nornially in circuit therewith adapted to energize said electromagnet to a limited extent only, to

cause the display of its signal when the said line circuit is closed at the sub-station, and having a second energizing winding 'in circuit with said testing contact piece, and. a cord circuit adapted to make connection with theline contact pieces of said switching terminal, and to complete a circuit through the second energizing winding of said electromagnet to cause a greater energization thereof, whereby said signal is elfaced and the normal connection of the first energizing winding is destroyed.

2. In a telephone exchange system the combination of a telephone line connecting a sub-station with the central o'llice, a switching terminal having two contact pieces conductively united to the two limbs of the telephone line and a testing contact piececonnected in a circuit local to the exchange, said testing contact piece being so arranged as to be brought into directelectrical connection with one of the said line contact pieces when a cord circuit is connected. with said switching terminal, a signal receiving clectro-- magnet associated with said line, having an energizing winding and source of current normally in circuit therewith adapted to energize said electromagnct to a limited ex tent only to cause the display of its signal when the said line .circuit is' closed at the substation, and having a second energizing winding in circuit with said testing contact piece, and a cord circuit adapted to make connection with the line contact pieces of said switching terminal, and to complete a circuit through thesecond energizing winding of said electromagnet to cause a greater energization thereof, whereby said signal is efiaced' and the normal connection ofthe first energizing winding is destroyed.

3. In a telephone exchange system the combination of a telephone line connecting a sub-station with the central ollicc, a signal receiving electromagnet associated with said line having an energizing winding and source of current normally in circuit therewith adapted to energize said electroinagnet to a limited extent only to cause the display of its signal when the said line circuit is closed at the sub-station, a spring jack associated with the line having a contact piece connected with each of the two limbs of the line and a third contact piece connected with a second energizing winding of said electromagnet, and lneans at the central ollice for establishing a circuit through said third contact piece of thej ack and said energizing winding of the electromagnet to cause a greater energization thereof, whereby the said signal is eii'aced and the normal connection of the said first energizing winding is destroyed.

4. In a telephone exchange system the combination of a tclcphone'linc connecting a sub-station with the central ollice, a signal receiving electromagnet associated nith said line having an cnergizing \Yhldlllg and source of current normally in circuit there ith adapted to energize said clectromagnet to a limited extent onlytocause the display of its signal when the said line circuitis closed at the sub-station, a spring jack associated with the line having a contact piece connected with each of the two limbs of the line and a third contact piece connected with a second energizing winding of said electromagnet, and switching apparatus at the central oliice adapted to make connection with said spring jack, including a source of current and acounection plug, said connection plug having two contact pieces, oneadaptcd to register with one line contact piece of the spring jack, the other adapted to register with the other line contact piece and the third contact piece jointly, whereby connection is established with the line and a circuit is completed through the second energizing winding of said elcctromagnet to cause a greater energization thereof to eil'ace the said. signal and to destroy the normal connection ol" the said first energizing winding.

5. In a telephone cxclninge system the combination of a metallic telephone line conductively uniting a suhstation with the two line contact pieces of a switching terminal at an'energizmg winding and source of current tact iece associated with said switching ter- "ed to secure a eflace said signal.

mina -a cord circuit at the central ofiice adapted to make connection withsaidswitching ter inal and to complete a circuit therethroug -over the said te ephone line, signal ing mechanism, a signal receiving electromagnet controlling said mechanism having normally in circuit therewith adapted to secure a limited energization only of said electroma net over the telephone line under the .contro of the sub-station switch, whereby a limited movement of said signaling mechanism is caused'to display a signal, and a second energizing winding for said electromagnet connected with the third-contact said switching terminal, andinclu ed in a circuit established by the connection of said cord circuit tothe telephone line, and adaptreater energization of said electromagnet w ereby said signaling mechanism is caused to assume a third position'to 6. In a telephone exchange system the combination of a metallic telephone line conductively uniting a sub-station with the two line contact pieces of a switching terminal at the central office, a switch at the sub-station for controlling the flow of current over the,

said line through the sub-station, a third contact iece associated with said switchingtermina adapted to bebrought into circuit with one of the said line contact pieces upon the insertion of a plug, a cordcireuit at the central ofiice adapted to make connection with said switching terminal and to complete a circuit ther'ethrough over the said tele hone line, a connection plug associated wit said cord circuit having two contact pieces only, one of said contact pieces being ada ted to complete a connection between sai third contact piece and a line contact piece of the switching terminal when connection is made with said switchin terminal, signaling mechanism, a signzil receiving electromagnet controlling said mechanism having an energizing winding and source ol',eurrentnormally in circuit therewith adapted .to secure a limited ener ization on ly of said electromagnet over the telephone line under the control of the sub-station switch, whereby a limited movement of said signaling mechanism is caused to display a signal, a second energizing windirw for said electromagnet connected with the t hird con- .tact piece of said switching terminal, and iniece of under the c ontrol of the sub-station switch,

g 7. In a telephone exchange system the combination of a metallic telephone line conductively uniting a sub-station with the two line contact pieces of a switching terminal at the central office, a switch at the sub-station for controlling'the flow of current over thesaid line through the sub-station, a third contact piece associated with said switching terminal, a cord circuit at the central office adapted to make connection with said switching terminal and to complete a circuit therethrough over the said telephone line, signaling mechanism, a signal receiving electromagnet controlling said mechanism associated with said telephone line, said electromagnet having an energizing Winding and source of current normallyin circuit therewith adapted to secure a limited energization only of said electromagnet over the telephone line whereby a limitedmovement of said signaling mechanism is causedto display a signal,

a-second energizing winding for said electromagnet connected with the third contact piece of said switching terminal, and included in a circuit established by the connection of said cord circuit to the telephone line, and adapted to secure a greater energi'zation of said electromagnet whereby said signaling mechanism is caused to assume a third position to eiface said signal, and signaling mech anism associated with the cord circuit and under control of the sub-station switch when thetelephone line is switched for conversation.

8. In a telephone exchange system' the combination of a metallic telephone line con ductively uniting a sub-station with the two line contact pieces of a switching terminal at the central office, a switch at the sub-station 05 for controlling the flow of current over the said line through the sub-station, a third contact piece associated with said switching terminal, a cord circuit at the central ofiice adapted to make connection with said switching terminal and to complete a circuit there through over the said telephone line, signaling mechanism, a signal receiving electromagnet associated with said telephone line said electromagnet controlling said mechanism having an energizing winding and source) of current normally in circuit therewith adapted to secure a limited energization only of said electromagnet over the telephone line under the control of the sub-station switch whereby a limited movement of said signaling mechanism is caused to display a signal, a second energizing winding for said electromagnet connected' with the third contact piece of said switching terminal, and included in a circuit establishci. by the connection of saidcord circuit tk the telephon -line and adapted to secure a greater energizatidn of said electromagnet whereby said signaling mechanism is cause .1 to assume a third posi' 130 tion to efface said signal, signaling mechanism associated with the cord circuit and under control of the sub-station switch when the telephone line is switched for conversation, and means whereby the operator may determine the busy or idle condition of a tested line:

'9. In a telephone exchange system the combination of a metallic telephone line conductively uniting a sub-station with the two line contact pieces of a switching terminal at the central ofiice, a switch at the sub-station for controlling the flow of current over the said line through the sub-station, a third contact piece associated with said switching terminal adapted to be brought into circuit with one of the said line contact pieces upon the insertion of a plug, a,cord circuit at the central'ofi'ice adapted to make connection with said switching terminal and to complete a circuit therethrough over the said tele phone line, a connection plug associatedwith'-said cord circuit having two contact pieces only, one of saidicontact pieces being adapted to complete connectlon between said third contact pie e and a line contact piece of the switching terminal when connection is made with said switching terminal,

' signaling mechanism, a signal receiving electromagnet controlling said mechanism associated with said telephone line said electromagnet having an energizing winding and source of current normally in circuit therewith adapted to secure a limited energization only of said electromagnet over the telephone line under the control of thesub-station switch whereby a limited movement of said signaling mechanism is caused to display a signal, a second energizing winding for said electromagnet connected with the third contact piece of said switching terminal and included in a circuit established by the connection of said cord circuit to the telephone line and adapted to secure a greater energiz'ation of said electromagnet whereby said signaling mechanism is caused to assume a third position @toefl'ace said signal, and signalingmechanism associated with the cord circuit and under control of the sub-station switch when the telephone line is switched for conversation.

10. In a telephone exchange system the combination of a metallic telephone line con- (luctively uniting a sub-station with the two line contact pieces of aswitching terminal at the central office, a switch at the sub-station for controlling the flow of current over the said line through the sub-station, a third contact piece associated with said switching terminal adapted to be brought into circuit with one of the said line contact pieces upon the insertion of a plug, a cord circuit at the central oilice adapted to make connection with said switching terminal and to complete a circuit therethrough over the said tele- A piece ofthe switching terminal when conriection is made with the line, signaling mechanism, a signal receiving electromagnet controlling said mechanism associated with said telephone line, said electromagnet having an energizing winding and source of current normally in circuit therewith adapted to secure a limited energization only of said electroma net over the telephone line under the contro of the sub-station switch where-- by a limited movement of said signaling mechanism is caused to dis lay a signal, a second energizing winding for said electromagnet connected with the third contact piece of said switching terminaland included in a circuit established by the connection of said cord circuit to the telephone line and adapted to secure a greater energization of said electromagnet whereby said signaling mechanism is caused to assume a third osition to efi'ace said signal, signaling mec anism associated with the cord circuit and under control of the sub-station switch when the telephone line is switched for conversation, and means wherebythe operator may determine. the busy or idle condition of a tested line.

11. In a telephone exchange system," the combination of a telephone line connecting a substation with the central ofiice, an electromagnet having an energizing winding nor-. mally in circuit with said line, a call signal controlled bysaid electromagnet, a springjack associated with the line having a contact-piece connected with each of the two limbs of the line and a third contact-piece connected with an energizing winding of said electromagnet, switching apparatus at the central ofiice adapted to make connection with said springjack,said apparatus including a source of current and a connecting plug having contact-pieces adapted to register with the two line contact-pieces and the third contact-piece of said jack, whereby when connection is established with the'line a circuit will be completed through an energizing winding of saidelec'tromagnet to destroy the substation control of said call signal.

12. In a telephone exchange system, the combination of a telephone line connecting a substationwiththe central office, anelectro magnet having, an energizing winding normally in circuit with said line, a call signal adapted to be displayed .upon'the closing of the line circuit, a springjack associated with theline having a contact-piece connected with each of the two limbs of the line and a .third contact-piece connected with an ener gizing winding of said electromagnet, switchmg apparatus at the central oflice adaptedto make connection with said springjack, said apparatusincluding a source of current and a connecting plug having contactieces adapted to register with the two fine contactpieces of the springjack and tomodifythe circuit connections of the third contact- .piece of said springjack, whereby when connection is established with the line" the circuit connectionsof said eiectromagnet. will be altered. 10

In witness whereof, I hereunto subscribe my name this 28th day of July, A.D.,1904.

. HARRY: G. WEBSTER.

Witnesses: I

KEMPSTER B. MILLER, GRACE MITCHELL. 

